Thursday, March 08, 2007


I haven't been paying much attention to nerdcore, hardcore rap for computer geeks, but a former co worker just forwarded a YouTube link to a very cool piece.

For those not familiar with the Unix references in the rap, sometimes you need to stop a runaway program. On a Windows machine, you'd use the process manager (the thing that pops up when you hit ctrl-alt-del on newer Windows versions). On Unix, you use a command called "kill." There are various forms of kill that have different levels of severity.
  • The normal "kill" will send a "terminate" signal asking the program to stop running. The program may ignore the signal.
  • "kill -1" sends a "hang up" signal. Some programs will respond to this signal by reconfiguring or restarting themselves.
  • "kill -9" tells the operating system "do whatever it takes to shut this program down now." It does not give the program time to react. It simply takes the program down immediately.
In that case, why not use "kill -9" all the time? Many programs, as part of shutting down, will do things like record configuration changes you might have made or data they might have received. If you take the program out without warning, it won't be able to write that information and could lose data. So normally, you'll escalate to "kill -9" only in the most severe situations.

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